Three 10W C-band Power Amplifier Alternatives for use in TT&C-Transmitters

118 Pages·2015·3.5 MB·English

by  Fabian Eckholdt

Three 10W C-band Power Amplifier
Alternatives for use in
TT&C-Transmitters
Fabian Eckholdt
Master of Science in Electronics
Submission date: June 2015
Supervisor: Morten Olavsbråten, IET
Co-supervisor: Stein Hollung, Kongsberg Norspace
Norwegian University of Science and Technology
Department of Electronics and Telecommunications

Abstract
Thisthesisdescribesthefirststageindesigningandrealizingthree10WC-bandpower
amplifieralternativesbasedontheGaN-technologyforuseinKongsbergNorspace’future
TT&C-transmitters. Theoperationalfrequencyrangespannedfrom3.4GHzto4.25GHz.
Itwasdecidedtobuildonesingle-stageamplifierbasedonthe10WCGH40010Ftransistor
from Cree and two dual-stage amplifiers with a balanced second stage based on the 6W
CGH40006Ptransistor,fromthesamemanufacturer.AWilkinsonpowerdividerwasused
tofeedeachbranchinthesecondstage.
Inthedesignprocedure,sourceandloadpullsimulationswereperformedinorderto
retrieve the optimal impedances for each transistor and as a basis for the design of the
matchingnetworks. Byutilizingaloopingmethodinthedesignprocessofthematching
networks,itwaspossibletoobtainresultsthat,tosomeextent,fulfilledtherequirements.
SimulationsanddesignwerecarriedoutinADSbyKeysight(formerAgilent).
The simulated results showed that all three designs were capable of delivering 10W
outputpowerthroughoutthefrequencyband. Thesingle-stageamplifierobtainedasim-
ulated power added efficiency (PAE) above 45% at 40dBm output power, while the two
dual-stagedesignsachievedaPAEbetween41-44%and34-36%,respectively.
S-parametersimulationsreviledthatthesingle-stagedesignaccomplishedasmallsig-
nal gain of 11.3dB-11.7dB, while the input reflection coefficients varied between -3dB
and-5dB.Toachievetherequirementofhavingtheinputreflectioncoefficientslessthan
-10dB, the dual-stage designs utilized an attenuator with 1.5dB loss at the input match,
bothdesignsobtainedasmallsignalgainabove20dB.
Like the simulated results, the large signal measurements showed that the ampli-
fiers were capable of delivering 10W output power, except the single-stage design at
4.0375GHz (which were one of the test frequencies). The measured power added effi-
ciency for the single-stage amplifier varied between 27%-44%, while the two dual-stage
amplifiers obtained aPAE between 39-43% and 35-42%, respectively. This implied that
nonofthedesignsmanagedtofulfilltherequirementofhavingatotalpowerconsumption
lessthan25Woverthespecifiedfrequencyrange.
Asimulatedlargesignalstabilityanalysiswereperformedoneachdesignandthere-
sultsrevealedthatoneofthedual-stagedesignshadapotentialinstabilityaround790MHz,
andpracticalspectrummeasurementsconfirmedfrequencycomponentsat750MHz,1.51GHz
and2.25GHz.However,thespuriousfrequencycomponentshadnomeasurableimpacton
theperformance.
AsmallsectionpresentingthefutureprospectsintermsofutilizingtheGaN-technology
inSpaceandsuggestionsforfuturework,havealsobeenincluded.
The thesis concluded that several iterations must be done before an integration with
thetransmittercanbemade.
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Sammendrag
Dennemasteravhandlingenbeskriverdetførstestegetia˚ designeogrealiseretre10W
C-ba˚ndeffektforsterkeralternativerbasertpa˚GaN-teknologienforbrukiKongsbergNorspace’
fremtidigeTT&C-sendere. Denoperasjonellebndbreddenspentefra3.4GHztil4.25GHz.
Det ble bestemt a˚ lage en ett-trinns effektforsterker basert pa˚ 10W CGH40010F transi-
storen fra Cree, og to to-trinnsforsterkere med et balansert utgangstrinn basert pa˚ 6W
CGH40006Ptransistoren,fradensammefabrikanten. EnWilkinsoneffektdelerblebrukt
fora˚ matehvergreniandre-trinnet.
Idesignprosessenbledetutførtsourceogload-pullingfora˚finnedeoptimaleimpedansene
forhvertransistorogsomenbasisforutformingenavtilpasningsnettverkene.Veda˚benytte
segavloop-metodenidesigneprosessenavtilpasningsnettverkenebledetmuliga˚oppna˚et
resultatsom,tilenhvisgrad,tilfredsstiltekravene.Simuleringogutformingenavforsterkerene
bleutførtidataprogrammetADSfraKeysight(tidligereAgilent).
Simuleringsresultatervisteatdetredesignenehaddeallemulighettila˚levereeneffekt
pa˚ 10W pa˚ utgangen gjennom hele frekvensba˚ndet. Ett-trinnsforsterkeren oppna˚dde en
poweraddedefficiency(PAE)pa˚over45%ved40dBmutgangseffekt,mensto-trinnsforsterkerene
henholdsvishaddeenPAEmellom41-44%and34-36%vedsammeuteffekt.
S-parametersimuleringer viste at ett-trinnsdesignet oppna˚dde et sma˚signalgain mel-
lom 11.3dB-11.7dB, samtidig som refleksjonskoeffisientene pa˚ inngangen varierte mel-
lom -3db og -5dB. For a˚ oppna˚ kravet pa˚ -10dB til refleksjonskoeffisientene pa˚ inngan-
gen, ble to-trinnsforsterkerene designet med et 1.5dB dempeledd pa˚ inngangsmatchen.
Sma˚signalgainetforto-trinnsforsterkerenevarbeggeover20dB.
Ilikhetmeddesimulerteresultatene,vistedema˚lteresultateneatalletredesignklarte
a˚ levere 10W, bortsett fra ett-trinnsdesignet ved frekvensen 4.0375GHz (som var en av
testfrekvensene). Ma˚ltPAEfordensammeforsterkerenvariertemellom27%-44%,mens
to-trinnsforsterkereneoppna˚ddeeneffektivitetpa˚henholdsvis39-43%and35-42%.Disse
resultateneviseratingenavforsterkereneklartekravettileffektbrukpa˚ maksimalt25W.
Detbleogsa˚foretattensimulertstorsignalstabilitetsanalysepa˚hvertavdesignenenoe
somførtetilatmuligeustabiliteterblepa˚vistietavto-trinnsforsterkerenerundt790MHz.
Praktiske spektrumsma˚linger bekreftet frekvenskomponenter ved 750MHz, 1.51GHz og
2.25GHz, men disse uønskede frekvenskomponentene hadde ingen ma˚lbar innvirkning
pa˚ ytelsen.
Et avsnitt som presenterer fremtidsutsiktene pa˚ bruk av GaN-teknologien i verden-
srommetogforslagtilfremtidigarbeiderogsa˚ tattmed.
Avhandlingen konkluderer med at flere designiterasjoner ma˚ bli gjort før man kan
integrereenforsterkermedsenderen.
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Preface
ThisthesisissubmittedforthedegreeofMasterOfScience(MSc)attheDepartmentof
Electronics and Telecommunications, Norwegian University of Science and Technology
(NTNU). The work was carried out in the period January to June 2015 under the super-
vision of associate professor Morten Olavsbra˚ten (NTNU) and Stein Hollung, principal
RFdesignengineeratKongsbergNorspaceAS.TheassignmentwasgivenbyKongsberg
Norspace.
First, I would like to thank Kongsberg Norspace for giving me the opportunity to work
withthetopicofRFpoweramplifiersandSteinHollungforsupportandprovidingmewith
equipment. Iwouldalsoliketothankmysupervisor,MortenOlavsbra˚tenforassistingme
and as a source for motivation during this work. In addition, I would like to thank Tore
Landsem and Tore Berg at the mechanical workshop together with Terje Mathiesen and
hiscrewforcuttingtheheatsinkandproducingthePCB’s,respectively.
A special thanks to my friends and fellow students for five fun and unforgettable years.
Andlastbutnotleast,aspecialthankstoMarenandmyfamily.
Trondheim,Norway,June2015
FabianEckholdt
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Table of Contents
Abstract i
Preface v
TableofContents ix
ListofTables xii
ListofFigures xvi
Abbreviations xvii
1 Introduction 1
1.1 Telemetry,trackingandcommandsystem . . . . . . . . . . . . . . . . . 1
1.2 Motivationandgoal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.3 Requiredspecifications . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.4 Outlineofreport . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Preliminaries 5
2.1 ActiveTwo-PortNetwork . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.1 S-Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.3 StabilityandOscillations . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.3.1 Even-ModeOscillationsandSmall-SignalStabilityAnalysis . . . 7
2.3.2 Odd-ModeOscillationsandLarge-SignalStabilityAnalysis . . . 8
2.4 Efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.5 PowerAmplifierClasses . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.5.1 ClassA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.5.2 ClassB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.5.3 ClassAB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.5.4 ClassC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
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2.6 1dBCompressionpoint . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.7 GaNTechnology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.8 LoadPull . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.9 PowerDivider . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.9.1 WilkinsonPowerDivider . . . . . . . . . . . . . . . . . . . . . . 14
2.10 T-attenuator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.11 SimulationTool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.11.1 SmallSignal . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.11.2 LargeSignal . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.11.3 Optimizers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.12 Measurementmethods . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.12.1 Small-signalmeasurements . . . . . . . . . . . . . . . . . . . . 17
2.12.2 Largesingle-tonemeasurements . . . . . . . . . . . . . . . . . . 17
2.13 Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3 Designandtopology 19
3.1 PowerAmplifierTopologiesandArchitectures. . . . . . . . . . . . . . . 19
3.1.1 Design1: Single-stagePA . . . . . . . . . . . . . . . . . . . . . 19
3.1.2 Design2:Two-stagePAwithbalancedsecond-stageandjointout-
putmatch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.1.3 Design3: Two-stagePAwithbalancedsecond-stageandseparate
outputmatch . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.2 Componenttechnology . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.2.1 Transistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.2.2 Substrate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.2.3 PassiveComponents . . . . . . . . . . . . . . . . . . . . . . . . 23
3.3 QuiescentPoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.4 BiasNetwork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3.4.1 Design1: Single-stage . . . . . . . . . . . . . . . . . . . . . . . 24
3.4.2 Design2&3: Two-stage . . . . . . . . . . . . . . . . . . . . . . 25
3.5 Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.6 Designingmatchingnetworks-Generalapproach . . . . . . . . . . . . . 28
3.6.1 Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3.7 Designingmatchingnetworks-Specificapproach . . . . . . . . . . . . . 29
3.7.1 Design1: Single-Stage . . . . . . . . . . . . . . . . . . . . . . . 29
3.7.2 Design2&3: Two-Stage. . . . . . . . . . . . . . . . . . . . . . 31
3.8 WilkinsonPowerDivider . . . . . . . . . . . . . . . . . . . . . . . . . . 35
3.9 Measurementconfiguration . . . . . . . . . . . . . . . . . . . . . . . . . 35
3.9.1 Smallsignalmeasurements . . . . . . . . . . . . . . . . . . . . . 36
3.9.2 Largesignalmeasurements . . . . . . . . . . . . . . . . . . . . . 36
4 Results 39
4.1 Results-Design1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
4.1.1 Smallsignalresults . . . . . . . . . . . . . . . . . . . . . . . . . 39
4.1.2 Largesignalresults . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.2 Results-Design2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
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